連線池單例模式

1.私有化ComboPooledDataSource將其作為屬性，使其實現單例
2.DataSourceFactory實現懶漢模式,這樣作為屬性的連線池cpds也就變為了單例
3.從連線池中獲取連線Connection

程式碼如下：

package com.tcb.dao.uitls;

import java.sql.Connection;

import com.mchange.v2.c3p0.ComboPooledDataSource;

/*
 * 連線池單例模式
 * 
 * 1.私有化ComboPooledDataSource將其作為屬性，使其實現單例
 * 2.DataSourceFactory實現懶漢模式,這樣作為屬性的連線池cpds也就變為了單例
 * 3.從連線池中獲取連線Connection
 */
 

public class DataSourceFactory {
    //1.私有化ComboPooledDataSource將其作為屬性，使其實現單例
    private ComboPooledDataSource cpds;

    //2.DataSourceFactory實現懶漢模式
    //2.1私有化構造方法--並初始化cpds
    private DataSourceFactory() {
        cpds = new ComboPooledDataSource("c3p0-config");
    }
    //2.2 私有化屬性
    private static
 
 DataSourceFactory sFactory = null;
    //2.3 返回SessionFactory單例
    public static DataSourceFactory getSessionFactoryInstance() {
        if (sFactory == null) {
            sFactory = new DataSourceFactory();
        }
        return sFactory;
    }

    //3.從連線池中獲取連線Connection
    public Connection getSession
 
() throws Exception {
        System.out.println("cpsd========="+cpds);
        Connection connection = cpds.getConnection();
        System.out.println("connection========="+connection);
        return connection;
    }

    public static void main(String[] args) {
        //測試
        DataSourceFactory dataSourceFactory=DataSourceFactory.getSessionFactoryInstance();
        DataSourceFactory dataSourceFactory2=DataSourceFactory.getSessionFactoryInstance();
        try {
            dataSourceFactory.getSession();
            dataSourceFactory.getSession();
            dataSourceFactory.getSession();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

測試結果：